1. Field of the Invention
The present invention relates to a punching method using a punch for forming a through-hole in a workpiece by punching the workpiece using a punch and a punch for punching, which is employed for carrying out the method.
2. Description of the Related Art
Such a punching method using a punch and a punch for punching are known from the Japanese Patent Application Laid-open 2006-305599.
Conventionally, a punch used for punching a workpiece is entirely solid, and thus has a high rigidity. This makes it possible to enhance the precision in dimensions of the hole formed by the punching. In this case, in order to improve the durability of a tooth portion of the punch, attention has been directed to improvements in the material of the punch and the thermal processing performed thereon. However, even such approaches have certain limitations.